Bei einem chirurgisches Instrument (2) miteiner Tulpe (10), wobei die Tulpe (10) einen Druckring (19, 22, 18) zur Aufnahme einer Pedikelschraube (7) aufweist, sollder Druckring (19, 22, 18) auswechselbar an der Tulpe (10) angeordnet sein.The surgical instrument (2) has a pressure ring which is arranged on tulip, for receiving a pedicle screw. A guide wire is inserted into opening of extension shaft. A web is mounted on an inner side of the pressure ring. Several grooves are formed on the screw head.
